now, keeping in mind that there are 60 minutes in an hour, that means Jim did 30 laps in 60 minutes then.
now, then we can just multiply each fraction by the "other's denominator" to get a common denominator for both.
[tex]\bf \stackrel{Tim}{\cfrac{16}{40}}\implies \cfrac{2}{5}\qquad \qquad \stackrel{Jim}{\cfrac{30}{60}}\implies \cfrac{1}{2}\\\\
-------------------------------\\\\
\cfrac{2}{5}\cdot \cfrac{2}{2}\implies \boxed{\cfrac{4}{10}}\qquad \qquad \cfrac{1}{2}\cdot \cfrac{5}{5}\implies \boxed{\cfrac{5}{10}}[/tex]
the fastest is the one who did more laps per the same minutes, Tim did 4 in 10 minutes, whilst Jim did 5 in the same 10 minutes.
